Mail domain report: sidn.nl

SPF

pass

SPF record published

Found

Record: v=spf1 a:ops-relay03-p.sidn.nl a:ops-relay04-p.sidn.nl a:ops-relayf03-p.sidn.nl a:ops-relayf04-p.sidn.nl a:ops-monext02-p.sidn.nl ip4:94.198.154.51 include:spf.protection.outlook.com include:secumail.email ~all
DNS lookups: 8 of 10
Void lookups: 0 of 2

Checks

✓ No deprecated ptr mechanism #1

No ptr mechanism found in SPF record.
✓ 8 of 10 DNS lookups #2

SPF record needs 8 DNS lookups (limit is 10).
✓ Ends with ~all #3

SPF record properly uses ~all to restrict unauthorized senders.
✓ Record published #6

SPF record exists for this domain.
✓ Single record #16

Exactly one SPF record is published.
✓ Valid syntax #25

All SPF mechanisms and modifiers are valid.
✓ No void lookups #26

All include/redirect targets exist.
✓ No overly broad IP ranges #27

All ip4/ip6 ranges are narrow enough.

DMARC

pass

p=reject (_dmarc.sidn.nl)

Found

Record: v=DMARC1; p=reject; rua=mailto:dmarc@sidn.nl,mailto:dmarc@sidn-nl.uriports.com; adkim=r; aspf=r; np=reject; psd=n; t=n; sp=reject
Found at: _dmarc.sidn.nl
External report address: mailto:dmarc@sidn-nl.uriports.com (authorized)

Tag	Value	Meaning
v	DMARC1	Version
p	reject	Policy
sp	reject	Subdomain policy
rua	mailto:dmarc@sidn.nl,mailto:dmarc@sidn-nl.uriports.com	Aggregate report addresses
adkim	r	DKIM alignment (r = relaxed, s = strict)
aspf	r	SPF alignment (r = relaxed, s = strict)
np	reject
psd	n
t	n

Checks

✓ Policy: reject #4

DMARC policy is set to 'reject', which provides the strongest protection against email spoofing.
✓ Record published #5

DMARC record exists for this domain.
✓ Valid syntax #17

DMARC record syntax is valid.
✓ Applies to 100% of mail #18

DMARC policy applies to all failing mail.
✓ Aggregate reports enabled #19

Aggregate reports are sent to: mailto:dmarc@sidn.nl, mailto:dmarc@sidn-nl.uriports.com
✓ Subdomain policy: reject #20

Subdomains are covered by policy 'reject'.
✓ External report addresses authorized #29

Report addresses in other domains have published their authorization.

DKIM

warn

Selectors: selector2

Found

Selectors: selector2
_domainkey: NOERROR

Selector	Key	Flags
selector2	RSA 1024 bits

Checks

✓ Keys found: selector2 #7

DKIM keys found for this domain with selectors: selector2
!

1024-bit DKIM key

1024-bit RSA keys are the minimum and are considered weak today: selector2 (1024 bits). Rotate to a 2048-bit key.

#23
✓ No problematic flags #24

No keys in test mode, revoked, or limited to SHA-1.

DNSSEC

pass

Signed, DS published at parent

Found

DNSKEY records: Yes (2)
DS at parent: Yes
Algorithms: ECDSAP256SHA256 (13)
Key tags: 30794, 62949
Signatures valid until: 29 October 2026, 00:00 UTC

Checks

✓ Signed, DS published at parent #8

DNSSEC is enabled for this domain (DNSKEY and DS present), providing additional security for DNS lookups.
✓ Signatures valid until 2026-10-29 #21

DNSKEY signatures are valid until 2026-10-29T00:00:00Z.

MX

warn

1 mail server

Found

Priority	Host	Records	Reverse DNS
0	sidn-nl.v-v1.mx.microsoft	A 52.101.103.140 A 52.101.181.153 A 52.101.91.153 A 52.101.209.28 AAAA 2a01:111:f403:ca04::e AAAA 2a01:111:f403:ca04::9 AAAA 2a01:111:f403:ca3c::8 AAAA 2a01:111:f403:ca04::c	mail-miypr02cu00204.inbound.protection.outlook.com ✓ mail-wa4pr04cu00101.inbound.protection.outlook.com ✓ mail-matpr04cu00101.inbound.protection.outlook.com ✓ mail-cpjpr05cu00104.inbound.protection.outlook.com ✓ mail-db8pr02cu00106.inbound.protection.outlook.com ✓ mail-db7pr03cu00601.inbound.protection.outlook.com ✓ mail-zrxpr05cu00100.inbound.protection.outlook.com ✓ mail-db9pr02cu00204.inbound.protection.outlook.com ✓

Checks

✓ 1 MX record #9

Found 1 MX records for this domain.
✓ All hosts resolve #10

All MX records resolve to valid IP addresses.
✓ All hosts have IPv6 #11

All MX records resolve to IPv6 addresses.
!

Single MX host, no backup

Only one MX record found. For better email reliability, consider adding at least one backup MX server.

#12
✓ At most 5 MX records #13

Found 1 MX records, which is within the recommended range (1-5).
✓ No localhost targets #14

No MX records pointing to localhost found.
✓ No private IP addresses #15

No MX records resolving to private IP addresses found.
✓ No CNAME targets #22

No MX records point to a CNAME.
✓ Reverse DNS confirmed #30

All 8 MX addresss have a PTR record that resolves back to them.

TLS

pass

MTA-STS enforce · TLS-RPT · DANE on 1 of 1 MX hosts

Found

MTA-STS record: v=STSv1; id=20241021T111111Z;
Policy URL: https://mta-sts.sidn.nl/.well-known/mta-sts.txt
Mode: enforce
Allowed MX: sidn-nl.v-v1.mx.microsoft
Max age: 2419200 seconds
TLS-RPT record: v=TLSRPTv1; rua=mailto:tlsrpt@sidn-nl.uriports.com

DANE (TLSA records)

MX host	TLSA	DNSSEC
sidn-nl.v-v1.mx.microsoft	3 1 1 803f7447cc75b208… 3 1 1 cfd68bde4129c00a… 2 0 1 ea7a25255d111fc3… 2 0 1 c1ad7778796d20bc… 3 1 1 54883cc5f1849331…	Yes

Checks

✓ Record published #32

MTA-STS record found with id 20241021T111111Z.
✓ Policy enforced #33

The MTA-STS policy is enforced and cached for 672h0m0s.
✓ All MX hosts covered #34

Every MX host matches an mx: line of the MTA-STS policy.
✓ Reports enabled #35

TLS reports are sent to: mailto:tlsrpt@sidn-nl.uriports.com
✓ DANE on all MX hosts #36

All 1 MX host publish DNSSEC-validated TLSA records.

BIMI

warn

https://www.sidn.nl/assets/img/logo-bimi.svg

Found

Record: v=BIMI1; l=https://www.sidn.nl/assets/img/logo-bimi.svg; a=;
Found at: default._bimi.sidn.nl
Logo: https://www.sidn.nl/assets/img/logo-bimi.svg

Checks

!

No certificate (a=)

The logo is published without a Verified Mark Certificate. Gmail and Apple Mail only show BIMI logos with a VMC or CMC; Yahoo shows it without one.

#38
✓ DMARC meets BIMI requirements #39

DMARC is enforced on all mail, as BIMI requires.